<div class="play-button"
     [class.isPlaying]="isPlaying()"
     appTrackPlayOn="click"
     [track]="track"
     [tracks]="tracks">
  <button class="btn btn-round btn-brand" *ngIf="!isPlaying()">
    <i class="fa fa-play play"></i>
  </button>
  <button class="btn btn-round btn-brand" *ngIf="isPlaying()">
    <i class="fa fa-pause"></i>
  </button>
</div>
